This invention is an evolution of my Brazilian patent application PI 0804261-6 “Redutor de Velocidade Magnético Orbital”, that is a magnetic speed reducer with one single transmission ratio. In my patent application PI 0804261-6 “Redutor de Velocidade Magnético Orbital” each stage of reduction has one pair of magnetic poles rings and the speed reducer has a single transmission ratio, now in this invention, we have a speed change mechanism with more than one transmission ratio and for this we have more pairs of magnetic poles rings, working one pair or another, or working each pair alternately or pairs of magnetic poles rings with variation in the number of poles. There are known magnetic variable speed drives where increasing the transmission ratio do not increase the output torque and have low efficiency in many operating points. The speed changer mechanism using gears are widely used, but they have acoustic noise and do not have high efficiency.